1. Field of the Invention
The present invention relates to a cap with pressure valve removably attached to a filler neck for supply of water which is mounted primarily on the upper end of a radiator tank for vehicles.
2. Description of the Related Art
A conventional radiator cap with pressure valve has been formed as seen in FIG. 13 and a filler neck 6 mounted removably with the cap has been formed as seen in FIG. 14.
The cap with pressure valve comprises a cap body 8 to which are attached via a fitting metal 22 a packing retainer 18 having an annular sealing material 7 and a temple-bell-shaped valve retainer 23, with a pressurization valve 10 attached via a movable plate 24 to the foot of the valve retainer 23. A negative pressure valve 11 is disposed via a valve stem 25 at the center of the pressurization valve 10. The pressurization valve 10 is urged downward by a pressure spring 9 and the negative pressure valve 11 is urged upward by a negative pressure spring 26.
The filler neck 6 is formed as a short cylinder whose bottom has an opening defined by its inner flanged portion. The opening edge of the inner flanged portion provides a valve seat 3. The upper edge of the filler neck 6 is formed with a flanged portion 19 whose outer peripheral edge hangs down to a slight extent, with a cam face 20 provided on the edge of the hung portion.
A pair of notches 21 are opposed diametrically on the flanged portion 19. The notches receive a pair of locking claws 17 formed on the underside of the cap body 8 such that the locking claws 17 are firmly engaged with the cam face 20 by turning the cap body 8 whereby the cap body 8 is removably fastened to the filler neck 6.
The filler neck 6 is provided with a small-diameter pipe 1. The lower end opening of the filler neck 6 leads to the upper end of the radiator tank.
Also proposed is one having the small-diameter pipe 1 firmly fixed to the cap body 8 at its central portion as shown in FIG. 15. More specifically, the small-diameter pipe 1 is secured to the central portion of the cap body 8, the valve retainer 23 having spring properties is provided with a vent hole 27, and a negative pressure/pressurization valve 29 is attached to the valve retainer 23, the negative pressure/pressurization valve 29 having a negative pressure opening/closing slot 28.
In the above former and latter, their pressurization valves are both seated on the valve seat 3 of the filler neck 6. There was also a need to form the notches 21 and the cam face 20 on the flanged portion 19 of the filler neck 6. This necessitated a multiplicity of dies and fabrication steps for forming the filler neck 6, and a high precision finish. As a result, the manufacturing costs of the filler neck 6 tended to rise.